This application is for a five-year extension of funding for the Pediatric Eye Disease Investigator Group (PEDIG). PED is supported through a single grant to the PEDIG Coordinating Center (CC), which funds all aspects of the group either directly or through subcontracts. [unreadable] [unreadable] PEDIG was formed to conduct clinical research in strabismus, amblyopia, and other eye disorders that affect children. During its funding period since 1997, the network has conducted or is currently conducting one protocol in congenital esotropia and six protocols in amblyopia. In addition, several pilot studies have been conducted. By the time the funding specified in this application begins, it is expected that four new amblyopia protocols and one new strabismus protocol will have begun. The network has developed a standardized, computerized visual acuity testing protocol for children and a quality of life measurement instrument for treatment of amblyopia, which have been used in the PEDIG protocols and which will be a resource for other investigators. [unreadable] [unreadable] The rationale for a network such as PEDIG is that efficiency is enhanced and costs reduced by having a single ongoing infrastructure that is able to conduct multiple concurrent and consecutive studies. The start-up time to implement a new trial from the inception of the concept for the trial to initiation of recruitment is greatly shortened. The primary focus of PEDIG involves studies that can be conducted through simple protocols with limited data collection and implemented by both university-based and community-based pediatric eye care practitioners as part of their routine practice. The investigator group includes both pediatric ophthalmologists and pediatric optometrists in an open network as described in B2. This structure also provides for the opportunity to prospectively collect data using a standardized protocol outside of randomized trials. This includes common conditions for which natural history data are not available and uncommon conditions and/or treatments for which meaningful data could only be collected by a large number of investigators each contributing a few patients. The structure is not intended to support studies requiring complex procedures requiring extensive site training and/or expensive equipment with limited availability. [unreadable] [unreadable]